I've got a merc character I'm trying to turn into a regular follower. I've managed to turn him into a friend, but I'm trying to get rid of the option to pay zero gold and replace it with a regular "Follow me. I need your help" command. Yep, it does the same thing, but I'd prefer the regular command for immersion reasons.

If I had the courage to mess with the creation kit I'd love to make old characters of mine as followers.

But I don't have the answer for you. Try the mod section of this forum?

It can be done some way via the console commands. Someone back along told me how to do it with another mercenary/hireling character, however I've forgotten what they told me.